Electrical connectors for automotive applications are incorporated into circuits that monitor and/or control a broad range of vital vehicular functions. For example, steering, suspension and engine operating conditions are continuously monitored on many vehicles. Signals corresponding to sensed operating conditions may be transmitted to displays in the passenger compartment to enable the driver to take appropriate action in response to the displayed information. Other sensed conditions are monitored by on-board controls which automatically alter some aspect of the vehicular performance to compensate for the sensed condition. The electronic circuitry also extends into several nonessential aspects of the vehicle performance, including climate control and sound systems. Vehicular manufacturers must be able to assure that all electronic systems are functioning properly when the vehicle is sold, and that the systems will continue to operate throughout the life of the vehicle.
The electrical connectors incorporated into the circuitry of an automotive vehicle are subjected to extreme environmental conditions, including broad ranges of temperature, exposure to moisture, subjection to almost continuous vibration during use and frequent subjection to direct physical shock. These environmental conditions may cause a terminal in a prior art connector to shift in the connector housing. Terminals of electrical connectors that are not properly inserted in their associated housing or that shift during use may not provide a high quality electrical connection. In an effort to ensure that electrical connectors perform properly, automotive manufacturers require connectors to have terminal position assurance (TPA) components. A TPA component should function to assure that each terminal is fully seated and locked in its connector housing.
Most electrical connectors for automotive applications are manufactured at a first location by an outside vendor, but are assembled and incorporated into the vehicle at a second location. The manufacturers of electrical connectors generally are highly skilled and very familiar with the construction and assembly of their connector, including the TPA component thereof. The assemblers of the connectors may not be as skilled, and generally will not be as familiar with the construction and assembly required for each connector they handle. As a result, there is a potential that a complex electrical connector having several components may be assembled improperly or incompletely. As a result, it is desirable to manufacture electrical connectors to minimize and simplify the amount of component assembly that must be carried out by the vehicular manufacturer.
Most prior art electrical connectors for vehicular applications include a plurality of deflectable locking latches unitarily molded as part of the connector housing. The latches are disposed to extend into the terminal receiving cavities of the housing. The locking latch initially will deflect during insertion of the terminal into the housing. However, upon complete insertion a locking window or other such structure on the terminal will align with the locking latch and will permit the locking latch to resiliently return toward an undeflected condition and into locking engagement with the terminal. These prior art connectors further include TPA components that are urged toward a fully locked position on the housing after the respective terminals have been inserted. The prior art TPA component typically includes a wedge-like projection disposed to extend into a space adjacent the deflectable locking latches of the housing or adjacent the terminals. An inability to fully insert the TPA component will be indicative of an improperly or incompletely inserted terminal. In this regard, complete advancement of the TPA component may be impeded by a deflectable locking latch that has not resiliently returned to an undeflected condition for engagement with the corresponding locking structure on the terminal. Most such prior art TPA components have been constructed to mount to the mating face of the connector and to advance in a direction extending generally parallel to the mating axis. Examples of such prior art connectors are shown in: U.S. Pat. No. 4,557,542 which issued to Coller et al. on Dec. 10, 1985; U.S. Pat. No. 4,714,437 which issued to Dyki on Dec. 22, 1987; and U.S. Pat. No. 4,826,452 which issued to Sian et al. on May 2, 1989. Connectors having TPA components that are mountable to the front mating face of the housing often are considered undesirable in that they limit options for designing the mating interface of pairs of electrical connectors, including environmental seals on the mating face. As will be explained further below, seals are essential for many electrical connectors on automobiles.
A very desirable electrical connector having a rear mounted TPA component is shown in U.S. Pat. No. 4,776,813 which issued to Wilson et al. on Oct. 11, 1988 and which is assigned to the Assignee of the subject invention. The rear mounting of the TPA component, as shown in U.S. Pat. No. 4,776,813, avoids interference between the TPA component and a front seal and/or a mating connector. The connector of U.S. Pat. No. 4,776,813 also is desirable in that the TPA component is locked to the housing in a pre-load condition which enables the terminals to be inserted. After insertion of the terminals the TPA component can be advanced forwardly to a final locked position on the housing which both assures complete seating of the terminals and which holds the locking latches of the housing in engagement with the respective terminals.
Although the connector shown in U.S. Pat. No. 4,776,813 is very effective, it is considered desirable to provide a connector with still further improvements. In this regard, it may be difficult to manipulate a rearmounted TPA component on connectors having a large number of terminals therein and a correspondingly large number of wires extending from the rear face. It also has been determined that quality control inspections are difficult to complete on connectors having deflectable terminal engaging latches disposed at interior locations on the housing. In particular, injection molding processes create the potential for "short shots" wherein an insufficient amount of molten plastic material is injected into some portion of a mold cavity. These "short shots" can result in some of the internally disposed terminal engaging latches of the housing being either omitted, inoperative or too weak. Terminal engaging latches within the housing make visual quality control very difficult.
Some electrical connectors with a large number of terminals include transversely mountable TPA components. More particularly, prior art connectors of this type have included terminals stamped and formed to include deflectable locking tangs which function as primary locks for engaging a corresponding structure in an associated terminal receiving cavity of the housing. The terminals further include a secondary locking surface or notch in the body of the terminal. The notch is disposed to align with a transversely extending keyway in the housing. A separate TPA component in the form of an elongated solid columnar member is insertable into the cavity of the housing. If the terminals are properly seated in the housing, the TPA component will advance transversely through the keyway to align with and engage the secondary locking surfaces or notches stamped into the terminals. TPA components of this general type prevent interference with seals disposed on either the forward mating face or the rearward wire receiving face of the terminal. Connectors of this type also avoid the interiorly disposed locking latches unitarily molded with the connector housing. Thus, the above described potential for short shots rendering some latches inoperative is completely avoided with connectors of this type. However, these prior art connectors do have some undesirable structural features. For example, the locking latches on the terminal can weaken the terminal and reduce the cross section of metal material for carrying signals from the wire to a mating terminal. Furthermore, the prior art connector of this type requires the transversely mounted TPA component to be separate from the connector housing and inserted only after all of the terminals have been inserted. This requirement imposes an inventory control problem on the vehicular manufacturer and creates the potential for having a TPA component improperly used or not used at all.
Japanese Patent Publication No. 64-45076 shows a connector with a transverse TPA component that is rotatable from a first alignment that permits insertion of terminals to a second alignment that locks the terminals in place. The connector shown in Japanese Patent Publication No. 64-45076 avoids the above described inventory control problems. However, the handle to effect rotation requires excessive space and can be difficult to manipulate.
The TPA components on most prior art connectors are substantially permanently locked in place. Thus, a defect in even one terminal may require replacement of the entire costly connector, with corresponding rewiring costs.
U.S. Pat. No. 4,959,023 issued to Watnabe et al. on Sept. 25, 1990. U.S. Pat. No. 4,959,023 shows an electrical connector having a TPA component received in the front mating end thereof. More particularly, the housing of the connector shown in U.S. Pat. No. 4,959,023 includes a transverse slot extending from the front mating face of the housing substantially entirely across the width of the housing for receiving the TPA component. The front mounted TPA component is indexable in a transverse direction after mounting in the front of the housing. In a first position the TPA component enables insertion of terminals into the housing, but in a second position the TPA component is intended to positively lock the terminals in the housing. In one embodiment of the connector shown in U.S. Pat. No. 4,959,023, the TPA component includes an array of forwardly disposed flexible retainer arms and a second array of rearwardly disposed terminal retaining portions. The forwardly disposed flexible retainer arms are positioned in the housing to engage stamped and formed retainer tongues at forward positions on the terminals when the terminals are fully inserted into the housing. The transverse indexing of the TPA component shown in U.S. Pat. No. 4,959,023 will cause the rearwardly disposed terminal retaining portions thereon to move partly into a rearwardly disposed window on the terminal. As explained above, front mounted TPA components generally are undesirable in that they limit design options for mateable pairs of connectors and may interfere with front mounted seals. Furthermore, an arrangement as shown in U.S. Pat. No. 4,959,023 with a front mountable and transversely indexable TPA component necessarily requires a large slot in the connector housing, thereby making the housing insufficiently sturdy and robust for use in the demanding automotive environment. The forwardly disposed stamped and formed retainer tongue on the terminals required for the connector of U.S. Pat. No. 4,959,023 may further weaken the terminals and will provide a smaller cross-sectional area for carrying signals through the terminal. Additionally, the more rigid terminal retaining portions of the TPA component shown in U.S. Pat. No. 4,959,023 are disposed to only engage one edge region of the terminal thereby providing lower pullout forces and enabling angular shifting of terminals in response to forces imposed upon the wires.
The front seals on electrical connectors typically are of U-shape cross-section. The base of the U-shape seal will seat against a portion of the connector housing. The arms of the U-shaped seal will project forwardly, with the space between the arms being dimensioned to sealingly engage a mating connector. In many situations, friction between the seal and the mating connector will cause the seal to dislodge during unmating. In other situations, the seal may be initially assembled incorrectly, with the arms of the U-shaped cross-section projecting rearwardly. This improper assembly may render the seal ineffective.
In view of the above, it is an object of the subject invention to provide an electrical connector having a transversely extending TPA component that can be mounted in the connector housing prior to insertion of the terminals therein.
Another object of the subject invention is to provide an electrical connector with a transversely mounted TPA component which performs a primary locking function for securely retaining the terminals in the housing.
An additional object of the subject invention is to provide an electrical connector with a TPA component that is alternately lockingly engagable with the housing in a pre-load condition and in a final locked condition.
Still a further object of the subject invention is to provide an electrical connector that can avoid deflectable locking means unitary with the housing and/or unitary with the terminal.
Yet a further object of the subject invention is to provide an electrical connector with transversely mounted TPA means and visually inspectible terminal locking means.
Another object of the invention is to provide a seal that is more securely engaged in the housing.
A further object of the invention is to provide a seal that can not be inserted incorrectly.